Railcar

ABSTRACT

According to a railcar, a low-floor underframe includes side beams to which side bodyshells are coupled, a high-floor underframe includes a center sill disposed to extend in a car longitudinal direction at a center in a car width direction and a body bolster coupled to this center sill and to be an installation portion of a bogie, and the body bolster is coupled to the side beam by a coupling member. Thus, the car end compression load input to the high-floor underframe can be directly transmitted from the center sill and the body bolster to the side beams via the coupling member. This can disperse the car end compression load on the side bodyshells to ensure the car strength against the car end compression load.

TECHNICAL FIELD

The present invention relates to a railcar, and especially relates to arailcar that ensures car strength against a car end compression load.

BACKGROUND ART

A railcar that forms high floors only at bogie portions at car end sidesand forms a low floor at a central portion in a car longitudinaldirection has been known. For example, Patent Literature 1 discloses anunderframe structure in such a partially-low-floor car. Specifically, atechnique that constitutes an underframe from a first floor-surfaceunderframe (a low-floor underframe), a second floor-surface underframe(a high-floor underframe) higher than this first floor-surfaceunderframe by a predetermined height, and a center sill structureportion (a coupling member) that couples this first floor-surfaceunderframe to this second floor-surface underframe is disclosed.

CITATION LIST Patent Literature

Patent Literature 1: Japanese Unexamined Patent Application PublicationNo. 2012-210887 (for example, paragraphs 0021 to 0023 and FIG. 1).

SUMMARY OF INVENTION Technical Problem

However, in the above-described conventional technique, the center sillstructure portion (the coupling member) is disposed at a position thatcouples a center sill of the first floor-surface underframe (thelow-floor underframe) to a center sill of the second floor-surfaceunderframe (the high-floor underframe). Thus, there has been a problemthat a car end compression load input to the second floor-surfaceunderframe is easily transmitted to only the first floor-surfaceunderframe to make it difficult to disperse on another structure; thus,it is difficult to ensure car strength against the car end compressionload.

The present invention has been made to solve the above-describedproblem, and it is an object of the present invention to provide arailcar that ensures car strength against a car end compression load.

Solution to Problem

A railcar according to claim 1 includes a low-floor underframe disposedat a center portion in a car longitudinal direction, high-floorunderframes arranged at one side and another side in the carlongitudinal direction across the low-floor underframe, and upper andlower positions of the high-floor underframes being set higher thanupper and lower positions of the low-floor underframe, and couplingmembers that couple the low-floor underframe to the high-floorunderframes in postures that incline downward from the high-floorunderframes toward the low-floor underframe, and the low-floorunderframe includes side beams to which side bodyshells are coupled, thehigh-floor underframe includes a center sill disposed to extend in thecar longitudinal direction at a center in a car width direction, and abody bolster to which the center sill is coupled to be an installationportion of a bogie, and the body bolster of the high-floor underframe iscoupled to the side beams of the low-floor underframe by the couplingmember.

The railcar according to claim 2 is the railcar according to claim 1,and the high-floor underframe includes side beams, and the sidebodyshell includes a first side post coupled to the side beam of thelow-floor underframe at a lower end to be disposed to extend in the carup and down direction, and a first frame member that couples the firstside post to the side beam of the high-floor underframe and is disposedto extend in the car longitudinal direction.

The railcar according to claim 3, in the railcar according to claim 2,includes a second-floor floor member disposed above the low-floorunderframe of a car to support a floor surface of a second-floor, and anupper end of the first side post of the side bodyshell is coupled to thesecond-floor floor member.

The railcar according to claim 4 is the railcar according to claim 3,and the side bodyshell includes a second side post coupled to the sidebeam of the high-floor underframe at a lower end to be disposed toextend in the car up and down direction, and the second side post of theside bodyshell is disposed at a position approximately corresponding toa position where the coupling member is coupled to the body bolster ofthe high-floor underframe, in the car longitudinal direction, and thesecond side post is coupled to the second-floor floor member.

The railcar according to claim 5 is the railcar according to claim 4,and an upper end of the second side post of the side bodyshell iscoupled to a roof bodyshell.

The railcar according to claim 6 is the railcar according to claim 5,and the coupling member, the first side post, the first frame member,and the second side post are formed of members with closed cross-sectionstructures.

Advantageous Effects of Invention

According to the railcar according to claim 1, the low-floor underframeincludes the side beams to which the side bodyshells are coupled, thehigh-floor underframe includes the center sill disposed to extend in thecar longitudinal direction at the center in the car width direction andthe body bolster coupled to this center sill and to be the installationportion of the bogie, and the body bolster of the high-floor underframeis coupled to the side beams of the low-floor underframe by the couplingmember. Thus, the car end compression load input to the high-floorunderframe can be directly transmitted from the center sill and the bodybolster of this high-floor underframe to the side beams of the low-floorunderframe via the coupling member. This can disperse the car endcompression load on the side bodyshells to ensure the car strengthagainst the car end compression load.

According to the railcar according to claim 2, in addition to the effectthat the railcar according to claim 1 provides, the side bodyshellincludes the first side post coupled to the side beam of the low-floorunderframe at the lower end to be disposed to extend in the car up anddown direction, and the first frame member that couples the first sidepost to the side beam of the high-floor underframe and is disposed toextend in the car longitudinal direction. Thus, the car end compressionload input to the high-floor underframe can be transmitted from the sidebeam of this high-floor underframe to the first side post via the firstframe member. That is, a route that transmits the car end compressionload to the side bodyshell is ensured. This facilitates to disperse thecar end compression load on the side bodyshell to ensure the carstrength against the car end compression load.

The railcar according to claim 3, in addition to the effect that therailcar according to claim 2 provides, includes the second-floor floormember disposed above the low-floor underframe of the car to support thefloor surface of the second-floor, and the upper end of the first sidepost of the side bodyshell is coupled to the second-floor floor member.Thus, the car end compression load input to the high-floor underframecan be transmitted to the second-floor floor member via the first sidepost. That is, the car end compression load can be dispersed on thesecond-floor floor member to ensure the car strength against the car endcompression load.

According to the railcar according to claim 4, in addition to the effectthat the railcar according to claim 3 provides, the side bodyshellincludes the second side post coupled to the side beam of the high-floorunderframe at the lower end to be disposed to extend in the car up anddown direction, and this second side post is coupled to the second-floorfloor member. Thus, the car end compression load input to the high-floorunderframe can be transmitted from the side beam of this high-floorunderframe to the side bodyshell and the second-floor floor member viathe second side post. This can disperse the car end compression load onthe side bodyshell and the second-floor floor member to ensure the carstrength against the car end compression load.

The second side post is disposed at the position approximatelycorresponding to the position where the coupling member is coupled tothe body bolster of the high-floor underframe, in the car longitudinaldirection. Thus, the car end compression load input to the high-floorunderframe to be transmitted from the center sill and the body bolsterof this high-floor underframe can be efficiently transmitted to thesecond side post via the body bolster and the side beam. Thisfacilitates to disperse the car end compression load on the sidebodyshell to ensure the car strength against the car end compressionload.

According to the railcar according to claim 5, in addition to the effectthat the railcar according to claim 4 provides, the upper end of thesecond side post of the side bodyshell is coupled to the roof bodyshell.Thus, the car end compression load input to the high-floor underframecan be transmitted to the roof bodyshell via the second side post. Thatis, the car end compression load can be dispersed on the roof bodyshellto ensure the car strength against the car end compression load.

According to the railcar according to claim 6, in addition to the effectthat the railcar according to claim 5 provides, the coupling member, thefirst side post, the first frame member, and the second side post areformed of the members with the closed cross-section structures. Thus,the buckling can be restrained when these respective members receive thecar end compression load. Consequently, the car strength against the carend compression load is ensured.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a side view of a railcar according to one embodiment of thepresent invention.

FIG. 2 is a cross-sectional view of the railcar along the line II-II inFIG. 1.

FIG. 3 is a cross-sectional view of the railcar along the line III-IIIin FIG. 1.

FIG. 4 is a front view of a carbody.

FIG. 5 is a partially enlarged top view of an underframe.

FIG. 6 is a partially enlarged cross-sectional view of the underframealong the line VI-VI in FIG. 5.

FIG. 7 is a partially enlarged top view of the underframe.

FIG. 8 is a partially enlarged cross-sectional view of the underframealong the line VIII-VIII in FIG. 7.

FIG. 9 is a partially enlarged cross-sectional view of the underframealong the line IX-IX in FIG. 7.

FIG. 10 is a partially enlarged cross-sectional view of the underframealong the line X-X in FIG. 8.

FIG. 11 is a partially enlarged cross-sectional view of the underframealong the line XI-XI in FIG. 5.

FIG. 12 is a partially enlarged cross-sectional view of the underframealong the line XII-XII in FIG. 5.

FIG. 13 is a partially enlarged cross-sectional view of the carbody.

DESCRIPTION OF EMBODIMENTS

Hereinafter, a description will be given of a preferred embodiment ofthe present invention with reference to the accompanying drawings.First, an overall configuration of a railcar 1 will be described withreference to FIG. 1 to FIG. 4.

FIG. 1 is a side view of the railcar 1 according to one embodiment ofthe present invention. FIG. 2 is a cross-sectional view of the railcar 1along the line II-II in FIG. 1. FIG. 3 is a cross-sectional view of therailcar 1 along the line III-III in FIG. 1.

As illustrated in FIG. 1 to FIG. 3, the railcar 1 mainly includes acarbody 2 internally including a passenger room and an equipment room,bogies 3 that supports this carbody 2 via air suspensions (notillustrated), and wheels 4 journaled to these bogies 3. The railcar 1 isa double-decker having upper and lower two-layer passenger roomstructures to be formed as a partially-low-floor car where parts of thebogies 3 in a front and a rear are high-floored and a part between thebogies 3 (a central portion in the car longitudinal direction) islow-floored.

The carbody 2 includes an underframe 10 that supports a floor surface ofa first floor, side bodyshells 60 whose lower ends are coupled to sideportions in a car width direction (a right-left direction in FIG. 2 andFIG. 3) of this underframe 10, end bodyshells 70 whose lower ends arecoupled to end portions in a car longitudinal direction (a right-leftdirection in FIG. 1) of the underframe 10, a roof bodyshell 80 coupledto upper ends of the side bodyshells 60 and the end bodyshells 70, and asecond-floor floor member 90 positioned between the underframe 10 andthe roof bodyshell 80 to support a floor surface of a second floor.

Connectors 5 are arranged at the end portions in the car longitudinaldirection of the underframe 10. The connector 5 projects outside the endbodyshell 70 in the car longitudinal direction. A plurality of seats 6are disposed side by side at floor surfaces supported by the underframe10 and the second-floor floor member 90. Baggage racks 7 are disposed toprotrude from inner surfaces of the side bodyshells 60 above theseplurality of seats 6. A plurality of window openings 61 are eachopeningly formed at the first floor and the second floor, and aplurality of door openings 62 are each openingly formed at the low-floorparts at the first floor, at the side bodyshells 60.

FIG. 4 is a front view of the carbody 2 and illustrates a state that anouter panel is removed to be a frame. As illustrated in FIG. 4, the endbodyshell 70 includes a pair of corner posts 71 disposed to extend in avertical direction (an up and down direction in FIG. 4) at both endportions in the car width direction, a pair of end posts 72 that havepredetermined distances in the car width direction between these pair ofcorner posts 71 to be disposed to extend in the vertical direction, andreinforced beams 73 that couple the corner post 71 to the end post 72 orthe end posts 72 together in the car width direction (a right-leftdirection in FIG. 4). Lower ends of the corner posts 71 and the endposts 72 are coupled to a first end beam 22 (the underframe 10, see FIG.5), and upper ends of the corner posts 71 and the end posts 72 arecoupled to the roof bodyshell 80, respectively.

Next, a detailed configuration of the underframe 10 will be describedwith reference to FIG. 5 and FIG. 6. FIG. 5 is a partially enlarged topview of the underframe 10. FIG. 6 is a partially enlargedcross-sectional view of the underframe 10 along the line VI-VI in FIG.5. FIG. 5 and FIG. 6 schematically illustrate the connector 5 and anenergy absorbing member 27 using two-dot chain lines.

As illustrated in FIG. 5 and FIG. 6, the underframe 10 includes alow-floor underframe 30 disposed at a center portion in the carlongitudinal direction (a right-left direction in FIG. 5), high-floorunderframes 20 arranged at one side and another side in the carlongitudinal direction across this low-floor underframe 30 and upper andlower positions are set higher than that of the low-floor underframe 30,and a coupling member 40 that couples this high-floor underframe 20 tothis low-floor underframe 30 in a posture that inclines downward fromthe high-floor underframe 20 toward the low-floor underframe 30 (seeFIG. 11), to be symmetrically formed in the car width direction.

The high-floor underframe 20 includes a pair of side beams 21 positionedat both sides in the car width direction (an up and down direction inFIG. 5) to be disposed to extend in the car longitudinal direction, afirst end beam 22 positioned at the end portion in the car longitudinaldirection to be disposed to extend in the car width direction, a secondend beam 23 disposed separated from this first end beam 22 to an innerside (a right side in FIG. 5) in the car longitudinal direction anddisposed to extend along the car width direction, a center sill 24coupled to a center in the car width direction of this second end beam23, at one end to disposed to extend in the car longitudinal direction,a body bolster 25 coupled to another end of this center sill 24 andinstalled across the pair of side beams 21 to be supported to the bogie3 (see FIG. 1), a plurality of floor-receiving beams 26 disposed toextend in the car width direction, the energy absorbing member 27arranged between the first end beam 22 and the second end beam 23,protruding members 28, and fuse members F.

The first end beam 22 is disposed separating outward in the carlongitudinal direction from end portions in the longitudinal directionof the pair of side beams 21. As described above, the lower ends of thepair of corner posts 71 are coupled to both ends in the longitudinaldirection of the first end beam 22, and the lower ends of the pair ofend posts 72 are coupled between these pair of corner posts 71. Thesecond end beam 23 couples both end portions in the longitudinaldirection of the pair of side beams 21 in the car width direction, andis positioned outward the wheels 4 (see FIG. 1) in the car longitudinaldirection.

The lower end of the end post 72 is internally inserted from an openingformed at a top surface of the first end beam 22 to be coupled to innersurfaces (two opposing surfaces in the car longitudinal direction and asurface opposed to the opening) of the first end beam 22. A plate-shapedreinforcing plate 29 is arranged inside the second end beam 23 in astate where an outer edge of the reinforcing plate 29 is coupled toinner surfaces (two opposing surfaces in the car longitudinal directionand an lower surface (a lower side in FIG. 6)) of the second end beam23.

The center sill 24 is formed with curving downward such that the endportion at a side of the second end beam 23 (a left side in FIG. 6)expands a dimension in an up and down direction toward the outside inthe car longitudinal direction. An outward end surface in the carlongitudinal direction of this end portion is an installation surface 24a on which the connector 5 is installed. In this embodiment, theinstallation surface 24 a of the center sill 24 is formed approximatelyflush with a surface at an outer side in the car longitudinal directionof the second end beam 23.

The body bolster 25 includes a body bolster center portion 25 a to whichthe other end at an inner side in the car longitudinal direction of thecenter sill 24 is coupled and disposed to extend in the car widthdirection, and body bolster extended portions 25 b coupled to the pairof side beams 21 and disposed to extend in the car longitudinaldirection to be positioned at both sides in the car width direction ofthe body bolster center portion 25 a. The body bolster 25 is formed tobe approximately H-shaped from a top view by these body bolster centerportion 25 a and body bolster extended portions 25 b.

The energy absorbing member 27 is a member for absorbing an energytransmitted from the first end beam 22 to the second end beam 23 suchthat, when the first end beam 22 moves toward the second end beam 23 inconsequence of the collision, the energy absorbing member 27 iscompressed to be deformed between these first end beam 22 and second endbeam 23. A base end of the energy absorbing member 27 is coupled to thecenter in the car width direction of the second end beam 23 in a statehaving a predetermined distance from the first end beam 22. As theenergy absorbing member 27, a known configuration is employable, thusomitting its detailed description.

Here, the center sill 24 is coupled to a surface at the inner side (theright side in FIG. 5) in the car longitudinal direction at approximatelya center in the car width direction of the second end beam 23. Theenergy absorbing member 27 is coupled to a surface at an opposite sideof this surface (the surface at the outer side in the car longitudinaldirection at the center in the car width direction of the second endbeam 23). Accordingly, the first end beam 22 is moved toward the secondend beam 23 in collision. When the energy absorbing member 27 iscompressed, the center sill 24 supports the second end beam 23 frombehind to ensure surely deforming (compressing) the energy absorbingmember 27, and the second end beam 23 deforms inward in the carlongitudinal direction to ensure reducing influence to the passengerroom.

The energy absorbing member 27 has the predetermined distance from thefirst end beam 22. Thus, by this distance, at an early stage in thecollision, this facilitates to transmit the load input to the first endbeam 22 only to the fuse members F. Accordingly, this can restrain theenergy absorbing member 27 from being a resistance against buckling ofthe fuse member F. That is, when inputting the intended load, the fusemember F can be surely buckled.

The protruding member 28 is a member for guiding a moving direction ofthe first end beam 22 to be disposed to protrude from a surface at aninner side in the car longitudinal direction of the first end beam 22toward the second end beam 23 along the car longitudinal direction. Thesecond end beam 23 includes a slide holding portion 23 a that is anopening penetrated along the car longitudinal direction. This slideholding portion 23 a receives a protruding distal end of the protrudingmember 28 (a distal end of the protruding member 28 is inserted into theslide holding portion 23 a). Thus, the protruding member 28 is held tothe slide holding portion 23 a slidably along the car longitudinaldirection. That is, this can regulate the moving direction toward thesecond end beam 23, of the first end beam 22, to the car longitudinaldirection, in the collision.

Here, the protruding member 28 is formed of a steel pipe with arectangular cross-section (steel material with a closed cross-sectionalstructure). The slide holding portion 23 a is formed as the openinghaving an inner shape identical to or slightly larger than an outershape of the protruding member 28. Forming the protruding member 28 withthe steel pipe can endure bend and torsion, compared with a case formedof an open cross-sectional or solid member having an identical weight.Accordingly, this ensures coupling strength between the first end beam22 and the second end beam 23 to ensure improvement of rigidity at a carend portion (an end portion in the car longitudinal direction).

As described above, the slide holding portion 23 a is formed as theopening penetrated along the car longitudinal direction at the secondend beam 23. Thus, when the first end beam 22 is moved toward the secondend beam 23, the slide holding portion 23 a can receive the protrudingmember 28 using a space at a back side (the inner side in the carlongitudinal direction) of the second end beam 23. That is, effect thatguides the first end beam 22 along the car longitudinal direction (slidedisplacement of the protruding member 28 with respect to the slideholding portion 23 a) can be maintained until just before the first endbeam 22 abuts on the second end beam 23.

Forming the slide holding portion 23 a as the opening of the second endbeam 23 improves space efficiency to not only ensure a passenger roomspace, but also ensure rigidity of the slide holding portion 23 a,compared with a case where a different member arranged at a top surfaceor a lower surface of the second end beam 23 slidably holds theprotruding member 28. Accordingly, the slide holding portion 23 a canstrongly hold the protruding member 28, and to that extent, the couplingstrength between the first end beam 22 and the second end beam 23 isensured to ensure the improvement of the rigidity of the car end portion(the end portion in the car longitudinal direction).

The fuse member F functions as a strength member that ensures therigidity of the car end portion (the coupling part between the first endbeam 22 and the second end beam 23) in normal operation. On the otherhand, the fuse member F is a member for allowing the first end beam 22to move toward the second end beam 23, by buckling when the loadreceived in the collision exceeds a predetermined value. The fuse memberF couples the first end beam 22 to the second end beam 23 along the carlongitudinal direction.

When the first end beam 22 collides with an oncoming car, the underframe10 compresses the fuse members F in the longitudinal direction betweenthe first end beam 22 and the second end beam 23. When the load exceedsthe predetermined value, the underframe 10 buckles this fuse member F toallow the first end beam 22 to move toward the second end beam 23.

That is, in a structure of a conventional product that breaks aplurality of coupling members such as rivets and bolts to allow thefirst end beam 22 to move toward the second end beam 23, influence of adimensional tolerance and a position tolerance of each of holes and thecoupling members gathers to facilitate to generate variation at breakingstrength. Thus, when the intended load is input, it has been difficultto allow the first end beam 22 to move toward the second end beam 23.However, as this embodiment, the structure that uses the buckling of thefuse member F ensures reducing variation of the load that allows thefirst end beam 22 to move toward the second end beam 23. Consequently,when the intended load is input, the first end beam 22 is allowed tomove toward the second end beam 23.

A pair of sets (slide mechanisms) including the protruding members 28and the slide holding portions 23 a are arranged. These pair of slidemechanisms are symmetrically disposed in the car width direction (in theup and down direction in FIG. 5) across the energy absorbing member 27.This can straightly guide (move along the car longitudinal direction)the first end beam 22 toward the second end beam 23, for example, evenwhen the oncoming car collides being biased in the car width directionto input an unbalanced load to the first end beam 22. Consequently, thefuse member F can be buckled by the intended load, and the energyabsorbing member 27 can be stably compressed along the car longitudinaldirection.

Similarly, a pair of fuse members F are arranged. These pair of fusemembers F are symmetrically disposed in the car width direction (the upand down direction in FIG. 5) across the energy absorbing member 27.This can uniform the load required for the deformation in the bucklingand after the buckling of the fuse member F, in the car width direction.That is, a posture with respect to the second end beam 23, of the firstend beam 22 inclines to ensure restraining the protruding member 28 fromgetting complicated inside the slide holding portion 23 a. Consequently,the slide displacement of the protruding member 28 with respect to theslide holding portion 23 a can be smoothly performed.

In this case, in this embodiment, the slide mechanism (the set of theprotruding member 28 and the slide holding portion 23 a) is disposedoutside the fuse member F in the car width direction (the upper side orthe lower side in FIG. 5). This facilitates to straightly guide (movealong the car longitudinal direction) the first end beam 22 toward thesecond end beam 23, for example, even when the oncoming car collidesbeing biased in the car width direction to input the unbalanced load tothe first end beam 22. Consequently, this facilitates to buckle the fusemember F by the intended load, and facilitates to stably compress theenergy absorbing member 27 along the car longitudinal direction.

Next, a detailed configuration of the fuse member F will be describedwith reference to FIG. 7 to FIG. 10. FIG. 7 is a partially enlarged topview of the underframe 10. FIG. 8 is a partially enlargedcross-sectional view of the underframe 10 along the line VIII-VIII inFIG. 7. FIG. 9 is a partially enlarged cross-sectional view of theunderframe 10 along the line IX-IX in FIG. 7. FIG. 10 is a partiallyenlarged cross-sectional view of the underframe 10 along the line X-X inFIG. 8.

As illustrated in FIG. 7 to FIG. 10, the fuse member F includes achannel material 50 that couples the first end beam 22 to the second endbeam 23, three plate-shaped bodies (a first plate member 51, a secondplate member 52, and a third plate member 53) fixedly secured to thischannel material 50 at regular intervals along the longitudinaldirection, a first gusset plate 54 installed across the first end beam22 and the channel material 50, and a second gusset plate 55 installedacross the second end beam 23 and the channel material 50.

The channel material 50, which is a member forming a frame of the fusemember F, is formed into an approximately U-shaped cross-section,including a web 50 a disposed to extend along the car longitudinaldirection (a right-left direction in FIG. 7) and a pair of flanges 50 bdisposed upright from both end portions (edge portions) of this web 50a. End surfaces in the longitudinal direction of the web 50 a and endsurfaces in the longitudinal direction of the flange 50 b are coupled toeach of the first end beam 22 and the second end beam 23, in a posturethat the web 50 a is parallel to the vertical direction (the flange 50 bis parallel to a horizontal direction).

In this way, the fuse member F is formed of the channel material 50 withthe approximately U-shaped cross-section. Thus, the fuse member Fensures the coupling strength between the first end beam 22 and thesecond end beam 23 to ensure the improvement of the rigidity of the carend portion in normal operation. On the other hand, when receiving theload that exceeds the predetermined value in consequence of thecollision, the fuse member F promptly buckles to allow the first endbeam 22 to move toward the second end beam 23.

In this embodiment, the fuse member F is arranged in a posture that anopening side (a side at which the flange 50 b is disposed upright) ofthe channel material 50 is opposed to an outside in the car widthdirection (a side of the protruding member 28) (see FIG. 5). Asdescribed later, the fuse member F can buckle in a mode that a back side(a lower side in FIG. 7) of the web 50 a is folded outside (anuprightly-disposed side (an upper side in FIG. 7) of the flange 50 b isan inside), with a reference position Ps as a base point. That is, thechannel material 50 can be folded to be doglegged to a directionseparated from the protruding member 28.

Accordingly, as described above, turning the opening side to theprotruding member 28 can reduce interference of the folded channelmaterial 50 to the protruding member 28 to ensure disposing the fusemember F close to the protruding member 28. This facilitates to obtain aguide effect in a sliding direction by the slide mechanism (theprotruding member 28 and the slide holding portion 23 a) to ensurestably forming the buckling of the fuse member F.

A thickness dimension of the channel material 50 (a dimension betweenouter surfaces of the pair of flanges 50 b, and dimensions in up anddown directions in FIG. 8 and FIG. 9) is configured approximatelyidentical to thickness dimensions of the first end beam 22 and thesecond end beam 23.

The first gusset plate 54 and the second gusset plate 55 are eachincluding upper and lower two plates. The top surface and a lowersurface of the first end beam 22 are bonded on the outer surfaces of therespective flanges 50 b of the channel material 50 by the first gussetplate 54, and the top surface and the lower surface of the second endbeam 23 are bonded on the outer surfaces of the respective flanges 50 bof the channel material 50 by the second gusset plate 55, respectively.

This can restrain a base end side (a coupling part to the first end beam22 or the second end beam 23) of the channel material 50 from bucklingon ahead, when the load in consequence of the collision acts. That is,the buckling in a mode that the channel material 50 is folded at anapproximately central part in the longitudinal direction (a regionbetween the first gusset plate 54 and the second gusset plate 55) can besurely formed. Consequently, the fuse member F (the channel material 50)is facilitated to buckle into an intended shape.

Here, at the fuse member F, a low-rigidity portion whose rigidity ispartially low is formed at the reference position Ps between the firstgusset plate 54 and the second gusset plate 55. With this referenceposition Ps (the low-rigidity portion) as the base point, the fusemember F is configured to buckle in the intended shape. The low-rigidityportion is formed by lowering an uprightly-disposed height of the flange50 b and thinning a plate thickness of the web 50 a. This low-rigidityportion will be described in the following.

At the fuse member F, the low-rigidity portion is formed at thereference position Ps such that the height disposed upright from the web50 a (a dimension in an up and down direction in FIG. 7) of the flange50 b is partially lowered. This can generate the buckling in the modethat the web 50 a can be folded, with the reference position Ps (thelow-rigidity portion) as the base point, when the load in consequence ofthe collision acts, to facilitate to buckle the fuse member F into theintended shape.

In particular, in this embodiment, at the channel material 50, theheight disposed upright from the web 50 a of the flange 50 b iscontinuously lowered toward the reference position Ps, in the regionbetween the first gusset plate 54 and the second gusset plate 55 (seeFIG. 7). That is, an outer edge of the flange 50 b is formed to beapproximately V-shaped. This can cause the load acted in consequence ofthe collision to stably focus on the reference position Ps to ensuresurely generating the buckling in the mode that the back side (the lowerside in FIG. 7) of the web 50 a is folded outside (theuprightly-disposed side (the upper side in FIG. 7) of the flange 50 b isthe inside) at the reference position Ps (the low-rigidity portion).

At the fuse member F, the low-rigidity portion is also formed at thereference position Ps by thinning the plate thickness of the web 50 a.This can cause the load acted in consequence of the collision to furtherfocus on the reference position Ps to ensure more surely generating thebuckling in the mode that the back side (the lower side in FIG. 7) ofthe web 50 a is folded outside (the uprightly-disposed side (the upperside in FIG. 7) of the flange 50 b is the inside) at the referenceposition Ps (the low-rigidity portion).

In this case, in this embodiment, fixedly securing the plate-shapedbodies (the first plate member 51, the second plate member 52, and thethird plate member 53) to the back surface (a surface at a side opposedto an uprightly-disposed direction of the flange 50 b) of the web 50 avaries the plate thickness of the web 50 a. Specifically, fixedlysecuring the first plate member 51 and the second plate member 52 havinga predetermined distance partially thins the plate thickness such thatthe plate-shaped body is not secured at the reference position Ps. Thiscan reduce man-hours to ensure reduction of a product cost to thatextent, for example, compared with a case of performing a cutting workto partially thin the plate thickness of the web 50 a.

The first plate member 51, the second plate member 52, and the thirdplate member 53 are formed into horizontally long rectangular shapes infront view. Accordingly, fixedly securing these respective plate members51 to 53 in postures that these longitudinal directions are set alongthe longitudinal direction of the channel material 50 (the web 50 a) caneasily form thin parts (parts at which the plate thickness is thinned)disposed to extend with an equal width in a direction (the up and downdirection in FIG. 8) perpendicular to the longitudinal direction of theweb 50 a.

Here, it is also considered that an opening is disposed at the web 50 ato form the low-rigidity portion at the reference position Ps. However,when the opening forms the low-rigidity portion at the referenceposition Ps, it cannot be regulated that the web 50 a is folded to whichdirection at the reference position Ps (the low-rigidity portion) tomake this folded direction instable. In contrast, the structure thatfixedly secures the plate-shaped bodies to the back surface of the web50 a to form the low-rigidity portion at the reference position Ps canstably regulate the direction that the web 50 a is folded. That is, thisensures surely generating the buckling in the mode that the back side(the lower side in FIG. 7) of the web 50 a is folded outside (theuprightly-disposed side (the upper side in FIG. 7) of the flange 50 b isthe inside) at the reference position Ps (the low-rigidity portion).

The first plate member 51, the second plate member 52, and the thirdplate member 53, as described above, are disposed at regular intervalsone another along the longitudinal direction of the web 50 a (a distancebetween the first plate member 51 and the second plate member 52, and adistance between the second plate member 52 and the third plate member53 are set to be identical).

In contrast, a group including the respective plate members 51 to 53 isdisposed being biased to a side of the second end beam 23 (a right sidein FIG. 8), in the longitudinal direction of the web 50 a. Therefore, adistance larger than the distances between the plate members 51 to 53 isformed between the first end beam 22 and the first plate member 51. Onthe other hand, a clearance is not formed between the third plate member53 and the second end beam 23 (that is, an edge portion of the thirdplate member 53 is fixedly secured (coupled) to the second end beam 23).

This enhances coupling strength at a coupling part between the fusemember F and the second end beam 23 to ensure restraining this couplingpart from being folded. Accordingly, this facilitates to buckle the fusemember F into the intended shape.

That is, the connector 5 is arranged at a bottom surface side of thesecond end beam 23, and this connector 5 is projected outside the firstend beam 22 in the car longitudinal direction (see FIG. 6). Therefore,the oncoming car may collide with the connector 5 on ahead, and in thiscase, the carbody 2 is deformed in a form that turns the end bodyshell70 (the first end beam 22) downward (lowers a head) by the load inputfrom the connector 5. Thus, large bending moment acts on the couplingpart to the second end beam 23, at the fuse member F.

Accordingly, the edge portion of the third plate member 53 is fixedlysecured to the surface at the outer side (a left side in FIG. 8) in thecar longitudinal direction of the second end beam 23 to enhance thecoupling strength at the coupling part between the fuse member F and thesecond end beam 23, thus ensuring resistance against the above-describedbending moment to ensure restraining the fuse member F from being foldedat the coupling part to the second end beam 23.

The group including the respective plate members 51 to 53 is disposedbeing biased to the second end beam 23 side (the right side in FIG. 8)in the longitudinal direction of the web 50 a to ensure forming changeof the plate thickness of the web 50 a at a first position P1 and asecond position P2, which are described later, and increasing a size ofthe second gusset plate 55. That is, this increasing of the size of thesecond gusset plate 55 will be also effective for resisting against theabove-described bending moment to restrain the fuse member F from beingfolded at the coupling part to the second end beam 23.

At the web 50 a of the channel material 50, fixedly securing the firstplate member 51, the second plate member 52, and the third plate member53 to the back surface thins the plate thicknesses at three positions:the reference position Ps, the first position P1 at a first end beam 22side of this reference position Ps, and the second position P2 at thesecond end beam 23 side of the reference position Ps.

Accordingly, when the load in the collision acts, while folding the fusemember F in the form that the back side (the lower side in FIG. 7) ofthe web 50 a is outside (the uprightly-disposed side (the upper side inFIG. 7) of the flange 50 b is the inside), as described above, at thereference position Ps, in contrast, the buckling in the mode that theback side of the web 50 a is folded inside (the uprightly-disposed sideof the flange 50 b is the outside) can be generated at the firstposition P1 and the second position P2. This ensures reduction of theload required for the deformation of the fuse member F after this fusemember F buckles.

In particular, in this embodiment, an edge portion of the first gussetplate 54 is positioned at the first position P1, and an edge portion ofthe second gusset plate 55 is positioned at the second position P2.Thus, at one or both of the first position P1 and the second positionP2, when the web 50 a is folded in the above-described form, the flange50 b constrained by the first gusset plate 54 or the second gusset plate55 can be cut along the edge portion of the first gusset plate 54 or thesecond gusset plate 55. Accordingly, after the fuse member F buckles,the load required for the deformation of this fuse member F can befurther reduced.

As described above, the lower end of the end post 72 is coupled to theinner surface of the first end beam 22, and the plate-shaped reinforcingplate 29 is arranged inside the second end beam 23, in a state where theouter edge of the reinforcing plate 29 is coupled to the inner surfaceof the second end beam 23.

In this case, the end post 72 and the reinforcing plate 29 are disposedin a straight line along the car longitudinal direction (see FIG. 10).These end post 72 and reinforcing plate 29, and the fuse member F aredisposed at positions that positions in the car width direction (an upand down direction in FIG. 10) at least partially overlap. That is, asviewed in the car longitudinal direction (viewed in a right-leftdirection in FIG. 10), the end post 72 and the reinforcing plate 29, andthe fuse member F at least partially overlap. In this embodiment, theend post 72 and the reinforcing plate 29, and the web 50 a of thechannel material 50 are disposed in a straight line along the carlongitudinal direction.

When the oncoming car collides with the end bodyshell 70 (see FIG. 4),that is, even when the oncoming car collides with a focus on a positionhigher than the first end beam 22, this facilitates to transmit the loadin the collision to the fuse member F (the web 50 a of the channelmaterial 50) via the end posts 72. Consequently, the fuse member F isbuckled to ensure absorption of the energy by the energy absorbingmember 27.

Regardless of whether the oncoming car collides at the position higherthan the first end beam 22 or directly collides with the first end beam22, the reinforcing plate 29 can support the fuse member F (the web 50 aof the channel material 50) that has received the load from a rearwardto ensure surely buckling the fuse member F (the channel material 50).

The description will be given returning to FIG. 5 and FIG. 6. Thelow-floor underframe 30 includes a pair of side beams 31 positioned atboth sides in the car width direction (the up and down direction in FIG.5) to be disposed to extend in the car longitudinal direction, and aplurality of floor-receiving beams 36 disposed to extend in the carwidth direction. As described above, the railcar 1 is formed as thepartially-low-floor car, and the underframe 10 is formed as anunderframe structure where the low-floor underframe 30 is coupled to thehigh-floor underframe 20 whose upper and lower positions are set higherthan that of this low-floor underframe 30 by the coupling member 40.This underframe structure will be described with reference to FIG. 11 toFIG. 13.

FIG. 11 is a partially enlarged cross-sectional view of the underframe10 along the line XI-XI in FIG. 5. FIG. 12 is a partially enlargedcross-sectional view of the underframe 10 along the line XII-XII in FIG.5. FIG. 13 is a partially enlarged cross-sectional view of the carbody2, and corresponds to a cross-section along the line XI-XI in FIG. 5.FIG. 13 illustrates only a main configuration by simplifying the drawingfor easily understanding.

As illustrated in FIG. 11 to FIG. 13, the coupling member 40 includes amain body member 41 formed of a steel pipe with the rectangularcross-section (steel material with the closed cross-sectionalstructure), and upper and lower pair of flange members 42 formed byprojecting out from outer surfaces at both end portions in thelongitudinal direction of this main body member 41, to couple a lowersurface of the body bolster extended portion 25 b at the body bolster 25of the high-floor underframe 20 to a top surface of the side beam 31 ofthe low-floor underframe 30.

The upper and lower pair of flange members 42 are formed as plate-shapedbodies with rectangular shapes in front view that are parallel oneanother. The upper side flange member 42 is formed having a size (awidth dimensions, and a right-left directional dimension in FIG. 12)coupled to the lower surface of the body bolster 25 (the body bolsterextended portion 25 b) and a lower surface of the side beam 21, at thehigh-floor underframe 20.

As described above, the high-floor underframe 20 includes the centersill 24 coupled to the center in the car width direction of the secondend beam 23 at the one end to disposed to extend in the car longitudinaldirection, and the body bolster 25 coupled to the other end of thiscenter sill 24 (see FIG. 5), and the side bodyshell 60 is coupled to theside beam 31 of the low-floor underframe 30. Accordingly, when a car endcompression load is input to the high-floor underframe 20, this car endcompression load can be directly transmitted from the center sill 24 andthe body bolster 25 of the high-floor underframe 20 to the side beam 31of the low-floor underframe 30 via the coupling member 40. This candisperse the car end compression load on the side bodyshell 60 to ensurecar strength against the car end compression load.

A first side post 63 coupled to the side beam 31 of the low-floorunderframe 30 at a lower end and disposed to extend in the up and downdirection (an up and down direction in FIG. 13), and a first framemember 65 that couples this first side post 63 to the side beam 21 ofthe high-floor underframe 20 and is disposed to extend in the carlongitudinal direction (a right-left direction in FIG. 13) are arrangedat the side bodyshell 60.

Accordingly, when the car end compression load is input to thehigh-floor underframe 20, this car end compression load can betransmitted from the side beam 21 of the high-floor underframe 20 to thefirst side post 63 via the first frame member 65. That is, a route thattransmits the car end compression load to the side bodyshell 60 can befurther ensured separately from the route by the coupling member 40.This facilitates to disperse the car end compression load on the sidebodyshell 60 to ensure the car strength against the car end compressionload.

In this case, the first side post 63 of the side bodyshell 60 is coupledto the second-floor floor member 90, at an upper end. Accordingly, whenthe car end compression load is input to the high-floor underframe 20,this car end compression load also can be transmitted to thesecond-floor floor member 90 via the first side post 63. This candisperse the car end compression load on the second-floor floor member90, in addition to the side bodyshell 60, to ensure the car strengthagainst the car end compression load.

A second side post 64 coupled to the side beam 21 of the high-floorunderframe 20 at a lower end and disposed to extend in the up and downdirection (the up and down direction in FIG. 13) is arranged at the sidebodyshell 60. This second side post 64 is coupled to the second-floorfloor member 90, in the middle of the longitudinal direction.Accordingly, when the car end compression load is input to thehigh-floor underframe 20, this car end compression load can betransmitted from the side beam 21 of this high-floor underframe 20 tothe side bodyshell 60 and the second-floor floor member 90 via thesecond side post 64. This can disperse the car end compression load onthe side bodyshell 60 and the second-floor floor member 90 to ensure thecar strength against the car end compression load.

In this case, the lower end of the second side post 64 of the sidebodyshell 60 is coupled to the side beam 21 of the high-floor underframe20 at a position approximately corresponding to a position at which thecoupling member 40 (the main body member 41 and the flange member 42) iscoupled to the body bolster 25 of the high-floor underframe 20 in thecar longitudinal direction (the right-left direction in FIG. 13). Thus,the car end compression load input to the high-floor underframe 20 to betransmitted from the center sill 24 and the body bolster 25 of thishigh-floor underframe 20 can be efficiently transmitted to the secondside post 64 via the body bolster 25 and the side beam 21. Thisfacilitates to disperse the car end compression load on the sidebodyshell 60 to ensure the car strength against the car end compressionload.

Further, the second side post 64 is coupled to the roof bodyshell 80 atan upper end. Accordingly, when the car end compression load is input tothe high-floor underframe 20, this car end compression load also can betransmitted from the side beam 21 of this high-floor underframe 20 tothe roof bodyshell 80 via the second side post 64. This also candisperse the car end compression load on the roof bodyshell 80, inaddition to the side bodyshell 60 and the second-floor floor member 90,to ensure the car strength against the car end compression load.

Here, similar to the main body member 41 of the coupling member 40, thefirst side post 63, the second side post 64, and the first frame member65 are formed of steel pipes with the rectangular cross-sections (steelmaterial with the closed cross-sectional structure). Accordingly, whenreceiving the car end compression load, buckling of these respectivemembers (the main body member 41, the first side post 63, the secondside post 64, and the first frame member 65) can be restrained.Consequently, the car strength against the car end compression load isensured.

Between the first side post 63 and the second side post 64, anintermediate post and a plurality of reinforcing beams are arranged (anyof them is not illustrated). The intermediate post is disposed to extendin the up and down direction (the up and down direction in FIG. 13) tocouple the second-floor floor member 90 to the first frame member 65.The reinforcing beams are disposed to extend in the car longitudinaldirection (the right-left direction in FIG. 13) to couple the first sidepost 63 to the intermediate post and the intermediate post to the secondside post 64.

On a surface at a car room side of the first side post 63, the secondside post 64, and the intermediate post (a side opposed to the outerpanel, and a near side in a paper of FIG. 13), a shear plate isstretched (fixedly secured). The shear plate, which is a plate-shapedbody with an approximately rectangular shape in front view, in thisembodiment, is arranged in a form installed across the first side post63 and the intermediate post, and across the intermediate post and thesecond side post 64. This ensures the car strength against the car endcompression load.

As described above, the present invention has been described based onthe above-mentioned embodiment. It will be appreciated that the presentinvention will not be limited to the embodiment described above, butvarious modifications are possible without departing from the technicalscope of the present invention.

While in the above-described embodiment, a case where the outer shape ofthe protruding member 28 is formed into the rectangular cross-sectionhas been described, this should not necessarily be construed in alimiting sense. The outer shape may be formed into a circular-shapedcross-section. While a case where the protruding member 28 is hollow hasbeen described, this should not necessarily be construed in a limitingsense. The protruding member 28 may be solid.

While in the above-described embodiment, as a method that varies theplate thickness of the web 50 a (partially forms portions whose platethicknesses are thin), a case where the plurality of plate-shaped bodies(the first plate member 51, the second plate member 52, and the thirdplate member 53) are fixedly secured to the web 50 a has been described,this should not necessarily be construed in a limiting sense. Forexample, performing a cutting work to the web 50 a may partially thinthe plate thickness of the web 50 a. The method that fixedly secures theplate-shaped bodies and the method that performs the cutting work may becombined.

1. A railcar comprising: a low-floor underframe disposed at a centerportion in a car longitudinal direction; high-floor underframes arrangedat one side and another side in the car longitudinal direction acrossthe low-floor underframe, and upper and lower positions of thehigh-floor underframes being set higher than upper and lower positionsof the low-floor underframe; and coupling members that couple thelow-floor underframe to the high-floor underframes in postures thatincline downward from the high-floor underframes toward the low-floorunderframe, wherein the low-floor underframe includes side beams towhich side bodyshells are coupled, the high-floor underframe includes acenter sill disposed to extend in the car longitudinal direction at acenter in a car width direction, and a body bolster to which the centersill is coupled to be an installation portion of a bogie, and the bodybolster of the high-floor underframe is coupled to the side beams of thelow-floor underframe by the coupling member.
 2. The railcar according toclaim 1, wherein the high-floor underframe includes side beams, and theside bodyshell includes: a first side post coupled to the side beam ofthe low-floor underframe at a lower end to be disposed to extend in thecar up and down direction; and a first frame member that couples thefirst side post to the side beam of the high-floor underframe and isdisposed to extend in the car longitudinal direction.
 3. The railcaraccording to claim 2, comprising a second-floor floor member disposedabove the low-floor underframe of a car to support a floor surface of asecond-floor, wherein an upper end of the first side post of the sidebodyshell is coupled to the second-floor floor member.
 4. The railcaraccording to claim 3, wherein the side bodyshell includes a second sidepost coupled to the side beam of the high-floor underframe at a lowerend to be disposed to extend in the car up and down direction, and thesecond side post of the side bodyshell is disposed at a positionapproximately corresponding to a position where the coupling member iscoupled to the body bolster of the high-floor underframe, in the carlongitudinal direction, the second side post being coupled to thesecond-floor floor member.
 5. The railcar according to claim 4, whereinan upper end of the second side post of the side bodyshell is coupled toa roof bodyshell.
 6. The railcar according to claim 5, wherein thecoupling member, the first side post, the first frame member, and thesecond side post are formed of members with closed cross-sectionstructures.